In the manufacturing process of liquid crystal displays (LCDs), there is a procedure of printing ID codes before slicing a large-size glass substrate, which includes providing a substrate ID for the large-size glass substrate itself (“substrate ID”) and providing panel IDs for small-size panels to be sliced from the large-size glass substrate (“panel IDs”). Each of the substrate ID code and the panel ID codes mainly consists of universal characters for identification by operators and two-dimensional (2D) symbols for identification by machines. These ID codes serve as identification marks of the related glass substrate and the panels, and are used for identification of the related glass substrate and the panels.
In the prior art, an alignment device for aligning the glass substrate is disposed at a back end of a platform. Therefore, in a process between loading the glass substrate to the platform and unloading the substrate from the platform, the printing operation is carried out only once when the glass substrate is conveyed from the back end to a front end of the platform and once when the glass substrate is conveyed from the front end to the back end of the platform. Therefore, the ID code printing operation is carried out on the glass substrate only twice in each flow process. However, as the sizes of glass substrates become increasingly larger in practical manufacturing processes, the number of panels of specific sizes that can be provided by each glass substrate also becomes increasingly larger, and this requires printing the ID codes more times under the same tact time conditions.
Furthermore, although printing of ID codes can be accomplished by increasing the number of printing laser heads or by simply increasing the number of times of printing when the number of panels to be sliced from a glass substrate is large, this will add to the production cost and decrease the production efficiency.